1. Field of the Invention
This invention relates to an image display apparatus and method, an information processing apparatus using the image display apparatus, and a storage medium storing a program for implementing the method.
2. Description of the Related Art
With development of multimedia in recent years, displays have come to be widely used in various scenes. Widespread use of devices using image sources in new digital formats, such as HDTV (High-Definition TV), MPEG, or JPEG, and sophistication of three-dimensional graphics not only increase the variety of processable images, but also make it possible to use displays in fields where no displays were conventionally used, thereby increasing the range of uses of displays.
For instance, projectors have come to be widely used at meetings or conferences and presentations. The projectors have been rapidly taking the place of conventional OHP's and prevailing with development of notebook personal computers (personal computer(s) will be hereinafter simply referred to as “PC” or “PC's”) and software for use in presentation. Further, the projectors have been changing in manners of connection with presentation tools, such as digital cameras, and other digital devices, as well as in functions thereof.
Another example is the improvement of display sections of portable information terminals. With increase in the number of pixels and the size of a screen, proliferation of color displays, and enhancement in gradation, the functions of such terminals have become more sophisticated and becoming closer to those of PC's.
In this situation, there are an increasing number of occasions when large-screen displays are used in classrooms, offices, homes and other places to provide various image sources e.g. of presentations, various data, video conferences, videos, and movies. Particularly at school and at office meetings, a display apparatus is conveniently used which is not only capable of displaying image information but also functioning as a whiteboard for displaying on a screen information plotted by a teacher or a person presiding a meeting by using an input device such as a digitizer pen.
FIG. 1 is a conceptual representation of a large-screen rear projection display used in a classroom or an office in place of a blackboard or a whiteboard, as an example of displays conventionally used on the above-mentioned occasions, while FIG. 2 shows the construction of the display.
In FIG. 1, reference numeral 601 designates an expositor, and reference numeral 602 a digitizer pen. Reference numeral 603 designates a line plotted on a screen in response to an image-plotting operation by the digitizer. Reference numeral 604 designates a screen of the large-screen display, which will be described in detail with reference to FIG. 2. Further, reference numerals 605 to 607 designate a plurality of windows (virtual child screens) on the PC display screen. In the illustrated example, a single PC is operated, and screens are displayed on the screen 604 according to respective application programs executed by the single PC.
In FIG. 2, reference numeral 701 designates the PC, and reference numeral 702 the large-screen rear projection display with the screen 604 appearing in FIG. 1. Reference numeral 704 designates digitizer detection means for detecting an image-plotting signal from the digitizer pen 602. Reference numeral 705 designates an output terminal via which an image signal is outputted from the PC, and reference numeral 706 a mouse input terminal functioning as a control signal input terminal via which the signal from the digitizer detection means 704 is inputted as a control signal for controlling the PC. Further, reference numeral 707 designates an operating system (OS) (1) of the PC 701, and reference numeral 708 an application program (1) which is one of application software programs operated on the PC 701. Reference numeral 709 designates a whiteboard software program (1) which is also one of the application software programs operated on the PC 701, particularly for realizing a whiteboard function on the PC 701. Actually, the OS (1) 707, the application program (1) 708 and the whiteboard software program (1) 709 are stored and exist as software programs in a storage medium for the PC 701. However, they are shown as false images in FIG. 2 to represent their operations on the PC 701.
Reference numeral 710 designates an image input terminal of the display 702, and reference numeral 711 an input image signal processing section. When an input signal is an analog signal, the input image signal processing section 711 performs adjustment of the input image signal to a predetermined amplitude and a predetermined DC level and converts the analog signal to a digital signal, while when an input signal is a digital signal, the section 711 performs conversion of the signal to a predetermined signal level and to a predetermined color format, and other processing. Reference numeral 712 designates a resolution conversion section that performs conversion of the resolution and frame rate of the image signal, reference numeral 713 an output image processing section that performs signal processing, such as gamma correction and division driving suitable for a device forming an image display section, and reference numeral 714 the image display section comprised of a device, such as a liquid crystal display, a cathode ray tube (CRT), or a plasma display panel (PDP), a drive circuit therefor, a light source and a projecting optical system. The section 714 corresponds to the screen 604 in FIG. 1.
Image-plotting operation is performed by the digitizer pen 602 on an image display surface of the image display section 714 (the screen 604), on which an image is displayed by staring and activating the whiteboard software program (1) 709 together with the application (1) 708 on the OS (1) 707 of the PC 701. The image-plotting signal generated by the digitizer pen 602 is detected by the digitizer detection means 704, and a coordinate signal obtained by converting the image-plotting signal is delivered to the mouse input terminal 706 to operate the whiteboard software program by mouse operation. According to the whiteboard software program, by selectively using one of tools available on the software including a pen and an eraser, the locus of the digitizer pen 602 is plotted on the display screen of the PC 701. This causes the motion of the pen on the screen 604 of the display 702 to agree with the locus of the pen on the display screen of the PC 701. Thus, it is possible to handle files on the display 702 and input characters according to character recognition software by using the digitizer pen 602, whereby the whiteboard function is realized.
In the conventional large-screen display 702, however, the display having the whiteboard function realizes the whiteboard function by the application software program on the PC 701. Therefore, after the power of the display 702 is turned on, it takes time from the start of the PC 701 to authentication of a network to which the PC 701 belongs and a user, and hence the user has to wait to use the display 702 for a considerable time. Further, the PC 701 connected to the display 702 is shared by a number of users, so that the use of the PC 701 is required to be permitted by taking adequate security into consideration, which complicates the process of authentication of the network to which the PC 701 belongs and a user. For instance, even if children happen to want to use the whiteboard function at school for trifles, or if office workers want to use the display 702 for memo paper while talking about a simple arrangement in a casual atmosphere, the above inconvenience at the start of the PC 701 hinders them from using the display 702.